/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: fzykd
 * Date: 2022-04-15
 * Time: 21:12
 */

class TreeNode{
    public char val;
    public TreeNode left;
    public TreeNode right;
    public TreeNode(char val){
        this.val = val;
    }

}

public class BinaryTree {
    public TreeNode createTree(){

        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');
        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        E.right = H;
        return A;

    }
    // 前序遍历 根左右
    public void preOrder(TreeNode root){
        if (root == null){
            return;
        }
        System.out.print(root.val+" ");
        preOrder(root.left);
        preOrder(root.right);
    }

    // 中序遍历 左根右
    public void inOrder(TreeNode root) {
        if(root == null) {
            return;
        }
        inOrder(root.left);
        System.out.print(root.val+" ");
        inOrder(root.right);
    }

    // 后序遍历  左右根
    public void postOrder(TreeNode root) {
        if(root == null) {
            return;
        }
        postOrder(root.left);
        postOrder(root.right);
        System.out.print(root.val+" ");
    }


}
